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<a href="log__fwd_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span><span class="comment"></span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="comment">/// @cond</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="comment"></span><span class="comment">// -^- Doxygen, please ignore the following.</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#define BOOST_FILESYSTEM_NO_DEPRECATED 1</span><span class="comment"></span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="comment">/// @endcond</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="comment"></span><span class="preprocessor">#include &lt;boost/filesystem.hpp&gt;</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="preprocessor">#include &lt;boost/filesystem/fstream.hpp&gt;</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="comment"></span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment">/**</span></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment"> * Flow module providing logging functionality.  While originally intended to</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * be used from within the flow::net_flow module&#39;s implementation, it can be used by general user code as well.</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> * All other Flow modules expose flow::log concepts when logging is relevant, so one way or another the user</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * is likely to have at least limited contact with flow::log if they use Flow at all.  (In particular, classes</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * and free/`static` functions in various Flow modules often take a Logger pointer as a constructor</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * or function argument respectively.  Hence to use such APIs one must instantiate a concrete Logger, the simplest</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> * choice being probably Simple_ostream_logger.)</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> *</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * (The general user [in their own, non-Flow-related code] may well</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * prefer to use another logging system directly instead; or use boost.log.</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> * However, we humbly recommend taking a look at flow::log as a possibility, as it is highly usable, yet fast, yet</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> * small and elegant enough to ensure complete visibility into its low-level behavior, including how that affects</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * performance.  Note also that this system easily integrates with others via log::Logger interface, so one can stack</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> * this on top of perhaps a lower-level logging facility.  The performance cost of this is essentially 1-2</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> * `virtual` pointer lookups per log-message call.)</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> * Log philosophy of Flow is as follows.  The following is a list of goals; and for each item, sub-item(s)</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> * explain how this goal is accomplished.</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> *</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> * - Flow is a library or set of libraries -- not an application or set of applications -- so logging has to flexibly</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> *   work with any logging system the user code may use.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *   - The Logger interface provides a way to efficiently log to an arbitrary logging output; the flow::log</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> *     user must provide a simple Logger implementation that fills in what Logger::should_log() and</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *     Logger::do_log() mean.</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> *   - To ensure maximum simplicity and usability right out of the box,</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *     flow::log provides a Logger implementation, Simple_ostream_logger, which will log to standard `ostream`s</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *     (including `cout` and `cerr`).  The user can just use this out of the box and not even have to implement</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> *     the (already trivial) Logger interface.  (Probably most larger projects would need to go beyond this.)</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> * - The logging system has to provide both error messages and informational or trace messages, and these</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> *   should be easily distinguishable once passed on to the user&#39;s supplied arbitrary logging output(s).</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> *   - There are at least 3 message severities, and they are passed to the Logger implementation, so</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> *     that this can be translated as necessary into the user&#39;s logging output(s).</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> * - The logging system is not a replacement for error reporting by Flow APIs.</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> *   - flow::Error_code and flow::error provide at least error code reporting (in addition to log calls)</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> *     where possible and applicable.</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> * - The logging should be possible to entirely enable, entirely disable, or some reasonable point</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> *   between these extremes.</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> *   - The Logger interface&#39;s Logger::should_log() method allows filtering messages by severity (e.g., allow</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> *     only WARNING messages) in any desired fashion.  There is now also support for setting filtering config</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> *     by &quot;component&quot; supplied essentially at the log message call site.</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> * - If a given message is not ultimately logged due its severity, it should induce no performance or resource</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *   penalty (such as that incurred by assembling the message string) beyond the severity check itself.</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> *   - The `FLOW_LOG_...()` macros work with the `Logger::should_log()`/`Logger::do_log()` APIs to only</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> *     construct the ultimate message string if the resulting message would be logged.</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> * - Logging should be simple without lots of extraneous features.</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> *   - A few simple-to-use macros are the main way to log messages; see those first.</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> *   - Every logged message just has a severity and component, which are `enum`s, and the text of the message.</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *     File/function/line and thread ID info are auto-obtained and maintained along with the</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> *     messages themselves, via the `FLOW_LOG_...()` macros.  The user need not worry about such mundane but tricky</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> *     details.</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> *   - The `FLOW_LOG_...()` macros assume that `get_logger()` (in the context where the macro is expanded)</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> *     returns a `Logger*` implementation, which is then used for the logging call(s) associated with the</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *     message -- typically first the Logger::should_log() check and then possibly the Logger::do_log()</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> *     message output.  Deriving from the supplied Log_context utility class is an easy way to make this</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *     `get_logger()` available all over the Flow modules&#39; implementations (and should indeed be a technique for the</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> *     user&#39;s own logging code, if indeed they decided to use flow::log themselves).</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> *</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * @internal</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> *</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * log_fwd.hpp is separate from log.hpp due to C++ circular dependency nonsense.  See util_fwd.hpp for some</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> * discussion on this same concept.</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> *</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> * @todo There are third-party logging systems including boost.log.  The to-do is to</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> * investigate using boost.log, partially or entirely replacing the manually implemented system.</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> * (To be honest I am rather partial to the simple but effective system already implemented, in particular</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"> * the performance-focused trickery.)  Boost is invaluable</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment"> * in many ways, and Flow modules use it extremely extensively, but my intuition says that in this case it may be</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"> * irrelevant.  Meanwhile, boost.log can, of course, be used within user&#39;s Logger interface implementation,</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"> * but that&#39;s not what this to-do is about; it&#39;s about actually placing it all over Flow&#39;s implementation and</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment"> * APIs *in place of* Logger, log::Sev, etc.  (Also, after a 5-minute glance at boost.log,</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> * I am noticing that some of its ideas I seem to have independently and</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> * unknowingly replicated here.  It is, however, simple stuff, not rocket science.)  My intuition is I hesitate to</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> * force-marry the Flow user to boost.log; the very simple Logger (abstract) interface is seemingly a gentler</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> * thing to force the Flow user into, at least relatively speaking.</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> *</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> * @todo Lacking feature: message IDs.  This is discussed a bit more in the log::Msg_metadata doc header.</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> *</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * @todo Lacking feature: `printf()`-style logging call sites, in contrast to the currently supported `ostream`</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> * fragment call sites.  So, like, `FLOW_LOG_WARNING_FMT(&quot;Hello, Mr. %s!&quot;, my_name.c_str())` could be used</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> * analogously to `FLOW_LOG_WARNING(&quot;Hello, Mr &quot; &lt;&lt; my_name &lt;&lt; &quot;!!&quot;)` (with `std::string my_name`).</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> * In terms of implementation, there is more to this than meets the eye perhaps; as `ostream`s potentially</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * store (formatting) state between totally separate invocations of `ostream&lt;&lt;`, whereas `printf()` style</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> * functions normally do not.  Internally, this likely allows for specially optimized logging code.</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> *</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> * @todo Lacking feature: boost.format-style logging call sites.  This is conceptually similar to -- and possibly even</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * entirely subsuming in backwards-compatible fashion -- the to-do just above for `printf()`-style logging.</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> * Likely both to-dos should be designed/implemented in one shot.  Moreover, it is possible (and would be</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * absolutely delightful if true) that boost.format&#39;s `format` class can be used entirely transparently on top</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> * of the `ostream`-focused existing flow::log API (such as FLOW_LOG_WARNING() and buddies)!</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> *</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> * @todo Lacking feature: log message rate-limiting.  This could actually mean a few things.  One is being able</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * to rate-limit the messages produced a given log call site per unit time; this might be the minimum for this to-do.</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> * This could be done by a dirty macro hack; or it could be done in more civilized fashion (while minding perf)</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> * by configuring it by message ID (but message IDs are optional and not implemented as of this writing anyway).</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> * Another rate-limiting thing is general controls on frequency of logging; though arguably that is more applicable</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> * to individual `Logger` implementations rather than as a mandatory-general mechanism.</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> *</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> * @todo Lacking feature: compiler hints for optimizing away log filter checks.  This is inspired by a certain</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> * other proprietary logging API in which we noticed attempts to give hints to the compiler as to how likely or</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> * unlikely the verbosity check is to return a true or false value, seemingly so that the compiler might</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> * optimize out the check and hence the entire log statement in some conditions; or *always* log others and</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> * skip the check in the optimized code.  I omit any details here, but that&#39;s the general idea.  I don&#39;t know</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> * how effective this is given that verbosities are configurable dynamically potentially; but look into it.</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> */</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1log.html">flow::log</a></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span>{</div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span> </div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span> </div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment">// Find doc headers near the bodies of these compound types.</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span> </div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="keyword">class </span>Async_file_logger;</div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="keyword">class </span>Buffer_logger;</div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="keyword">class </span>Component;</div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="keyword">class </span>Config;</div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="keyword">class </span>Logger;</div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="keyword">class </span>Log_context;</div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="keyword">struct </span>Msg_metadata;</div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="keyword">class </span>Ostream_log_msg_writer;</div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="keyword">class </span>Simple_ostream_logger;</div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span> </div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span> </div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">/* (The @namespace and @brief thingies shouldn&#39;t be needed, but some Doxygen bug necessitated them.</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"> * See flow::util::bind_ns for explanation... same thing here.) */</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"></span> </div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment">/**</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno"><a class="line" href="namespaceflow_1_1log_1_1fs.html">  155</a></span><span class="comment"> * @namespace flow::log::fs</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"> * @brief Short-hand for `namespace boost::filesystem`.</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment"> */</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceboost_1_1filesystem.html">fs</a> = <a class="code hl_namespace" href="namespaceboost_1_1filesystem.html">boost::filesystem</a>;</div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment"></span> </div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">/**</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment"> * Enumeration containing one of several message severity levels, ordered from highest to</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment"> * lowest.  Generally speaking, volume/verbosity is inversely proportional to severity, though</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"> * this is not enforced somehow.</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment"> *</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment"> * As the underlying type is `size_t`, and the values are guaranteed to be 0, 1, ... going from lowest</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment"> * to highest verbosity (highest to lowest severity), you may directly use log::Sev values to index into arrays that</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment"> * arrange one-to-one values in the same order.</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"> *</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment"> * The supplied `ostream&lt;&lt;` operator, together with this `enum`, is suitable for util::istream_to_enum().</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment"> * `ostream&gt;&gt;` operator is built on the latter and is also supplied.  Hence I/O of `Sev` is available out of the box;</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment"> * this enables parsing in boost.program_options among other things.</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment"> *</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment"> * ### Formal semantics of log::Sev ###</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment"> * From the point of view of all Flow code, the *formal* semantics of log::Sev are as follows:</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment"> *   - Sev::S_NONE has value 0 and is a start-sentinel.</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment"> *   - Non-sentinel severities follow, starting at 1 with no gaps.</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment"> *     - Ordinal comparison is meaningful; lower is termed as more severe/less verbose; higher is therefore</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"> *       termed as less severe/more verbose.  These are, formally, only terminology.</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment"> *   - Sev::S_END_SENTINEL is the end-sentinel.</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment"> *   - Sev::S_WARNING is and always shall be considered the *least severe* &quot;abnormal&quot; condition.  Any additional</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"> *     &quot;abnormal&quot; conditions shall always have more-severe (numerically lower) values.</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment"> *     As of this writing, within flow::log Flow module, this has only one practical meaning (but that could change):</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment"> *     Simple_ostream_logger directs WARNING-and-more-severe messages to its configured *error* stream (`os_for_err`);</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment"> *     while all the rest are directed to its configured other (regular) stream (`os`).  (For example these might</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment"> *     be set to `std::cerr` and `std::cout` respectively; or both to `std::cout`.)</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment"> *</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment"> * ### Informal semantics of log::Sev ###</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment"> * The following are not enforced by any code logic in the flow::log Flow module.  However we suggest users</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment"> * understand and consider these, as a haphazard approach to severity selection for a given log call site can</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment"> * cause significant operational problems in a high-volume production environment (at least).</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment"> *</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment"> * Generally, there are 2 types of log call sites: ones inside Flow; and ones outside (user code).  The former</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment"> * (inside Flow) are deliberately minimalistic, so as to use as few severities as possible and thus make</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment"> * severity selection maximally simple and, importantly, unambiguous.</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment"> *</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment"> * However, logging code outside Flow may require more sophisticated in-use severity sets.  Informally we *recommend*</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment"> * keeping it as simple as inside-Flow&#39;s scheme... if it is sufficient.  If it is not sufficient, the other</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment"> * severities may also be used.</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"> *</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment"> * The log::Sev values used inside Flow (the *minimalistic* set) are as follows.  (Brief meanings accompany them;</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment"> * see their individual doc headers for more detail.)  From most to least severe:</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment"> *   - Sev::S_FATAL: the program will abort shortly due to the condition that is being logged.  Usually an</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="comment"> *     `assert(false)` and/or `std::abort()` follows.  If you&#39;ve disabled abort-on-assertion-trip (`NDEBUG` is defined),</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment"> *     and there is no `std::abort()` or equivalent, then the program may continue, but subsequent behavior is</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment"> *     undefined.</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment"> *   - Sev::S_WARNING: abnormal condition is being logged, and its aggregate volume is not high enough to be classified</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment"> *     as TRACE instead to avoid perf impact.  (Other than possibly FATAL -- used in extreme cases -- no</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment"> *     other abnormal-condition `Sev` are in-use inside Flow nor will they be.)</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment"> *   - Sev::S_INFO: non-abnormal condition is being logged, and it&#39;s not so frequent in practice that enabling</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment"> *     this log level shall adversely impact performance.</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment"> *   - Sev::S_TRACE: like INFO, but enabling this log level *can* adversely impact performance.  However, entire</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment"> *     dumps of potentially large (in aggregate) data (such as packet contents) being processed are not included.</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment"> *   - Sev::S_DATA: like TRACE, but entire contents of potentially large (in aggregate) data (such as packet contents)</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment"> *     being processed are included in the message, which may lead to particularly large log output (if enabled).</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment"> *</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment"> * As of this writing the following log::Sev values are available for use (by user/non-Flow code) beyond the above</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"> * *minimalistic* set.  Potential subjective meanings are included, but user code can use whatever conventions that</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment"> * suit them best.</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment"> *   - Sev::S_ERROR: A non-FATAL abnormal condition subjectively more severe than WARNING.</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment"> *   - Sev::S_DEBUG: A non-abnormal condition with, perhaps, non-perf-affecting verbosity (a-la INFO) but subjectively</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment"> *     of less interest to a human glancing over a large-ish log snippet (a-la TRACE).</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment"> */</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno"><a class="line" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">  223</a></span><span class="keyword">enum class</span> <a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> : <span class="keywordtype">size_t</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span>{<span class="comment"></span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment">   * Sentinel log level that must not be specified for any actual message (at risk of undefined behavior such</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">   * as assert failure); but can be used for sentinel purposes such as specifying a log filter wherein</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment">   * no messages (not even Sev::S_WARNING ones) are shown.</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment">   */</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a9ed9d44ce5760f61ea506d5571343624">S_NONE</a> = 0,</div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment"></span> </div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment">   * Message indicates a &quot;fatally bad&quot; condition, such that the program shall imminently abort, typically due</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment">   * to immediately-following `assert(false)` and possibly `std::abort()`; or if aborts are disabled (such as</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment">   * via defining `NDEBUG`), and there is no explicit `std::abort()` or equivalent, then further</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment">   * program behavior is undefined.</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment">   *</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment">   * @note This severity *is* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment">   */</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04ac90b5a22c7659cc99e7a6d919a14b660">S_FATAL</a>,</div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"></span> </div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment">   * Message indicates a &quot;bad&quot; condition with &quot;worse&quot; impact than that of Sev::S_WARNING.</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment">   *</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment">   * @note If it&#39;s &quot;bad&quot; but frequent enough for TRACE, we strongly recommend to make it TRACE -- not ERROR.</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment">   *</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment">   * @note This severity *is NOT* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.  Informally we recommend projects</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment">   *       do not use it unless it is holistically necessary.</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment">   */</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04aac04e40d3b2f54f1f517d49594eb7849">S_ERROR</a>,</div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment"></span> </div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment">   * Message indicates a &quot;bad&quot; condition that is not frequent enough to be of severity Sev::S_TRACE.</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">   * These typically should occur with less frequency than INFO messages; however, it&#39;s not a hard rule.</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment">   *</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment">   * @note If it&#39;s &quot;bad&quot; but frequent enough for TRACE, it&#39;s TRACE by definition -- not WARNING.</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment">   *</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment">   * @note This severity *is* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment">   */</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a4aee6034ce9dbc2b5c36f27c80abe021">S_WARNING</a>,</div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment"></span> </div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment">   * Message indicates a not-&quot;bad&quot; condition that is not frequent enough to be of severity Sev::S_TRACE.</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment">   *</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment">   * @note That is, it&#39;s identical to WARNING *except* doesn&#39;t represent a &quot;bad&quot; situation.</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment">   *</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment">   * @note This severity *is* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.</span></div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment">   */</span></div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04ac238793326fae17afcc849e96b96e8e7">S_INFO</a>,</div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span><span class="comment"></span> </div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span><span class="comment">   * Message indicates a condition with, perhaps, no significant perf impact if enabled (like Sev::S_INFO)</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span><span class="comment">   * but of subjectively less interest to a human reader than INFO (hence, like Sev::S_TRACE in that respect).</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span><span class="comment">   *</span></div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span><span class="comment">   * @note This severity *is NOT* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.  Informally we recommend projects</span></div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span><span class="comment">   *       do not use it unless it is holistically necessary.</span></div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span><span class="comment">   */</span></div>
<div class="line"><a id="l00283" name="l00283"></a><span class="lineno">  283</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04aa6874010df179b46ffec47aaf9bc1358">S_DEBUG</a>,</div>
<div class="line"><a id="l00284" name="l00284"></a><span class="lineno">  284</span><span class="comment"></span> </div>
<div class="line"><a id="l00285" name="l00285"></a><span class="lineno">  285</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00286" name="l00286"></a><span class="lineno">  286</span><span class="comment">   * Message indicates any condition that may occur with great frequency (thus verbose if logged).</span></div>
<div class="line"><a id="l00287" name="l00287"></a><span class="lineno">  287</span><span class="comment">   * The line between Sev::S_INFO or Sev::S_WARNING and TRACE is as follows: The former is *not* allowed to classify</span></div>
<div class="line"><a id="l00288" name="l00288"></a><span class="lineno">  288</span><span class="comment">   * messages such that in realistic scenarios they would degrade performance, from processor cycles or log file I/O.</span></div>
<div class="line"><a id="l00289" name="l00289"></a><span class="lineno">  289</span><span class="comment">   *</span></div>
<div class="line"><a id="l00290" name="l00290"></a><span class="lineno">  290</span><span class="comment">   * @see Sev::S_DATA for an even-more-verbose severity, when it&#39;s frequent and potentially large in size in aggregate.</span></div>
<div class="line"><a id="l00291" name="l00291"></a><span class="lineno">  291</span><span class="comment">   *</span></div>
<div class="line"><a id="l00292" name="l00292"></a><span class="lineno">  292</span><span class="comment">   * @warning One MUST be able to set max severity level to INFO and confidently count that logging will not</span></div>
<div class="line"><a id="l00293" name="l00293"></a><span class="lineno">  293</span><span class="comment">   * affect performance.</span></div>
<div class="line"><a id="l00294" name="l00294"></a><span class="lineno">  294</span><span class="comment">   *</span></div>
<div class="line"><a id="l00295" name="l00295"></a><span class="lineno">  295</span><span class="comment">   * @note This severity *is* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00296" name="l00296"></a><span class="lineno">  296</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.</span></div>
<div class="line"><a id="l00297" name="l00297"></a><span class="lineno">  297</span><span class="comment">   */</span></div>
<div class="line"><a id="l00298" name="l00298"></a><span class="lineno">  298</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a3ee808b04c34bf6c110e3754de277f7b">S_TRACE</a>,</div>
<div class="line"><a id="l00299" name="l00299"></a><span class="lineno">  299</span><span class="comment"></span> </div>
<div class="line"><a id="l00300" name="l00300"></a><span class="lineno">  300</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00301" name="l00301"></a><span class="lineno">  301</span><span class="comment">   * Message satisfies Sev::S_TRACE description AND contains variable-length structure (like packet, file) dumps.</span></div>
<div class="line"><a id="l00302" name="l00302"></a><span class="lineno">  302</span><span class="comment">   * If these are allowed to be logged, resulting log file might be roughly similar to (or even larger than)</span></div>
<div class="line"><a id="l00303" name="l00303"></a><span class="lineno">  303</span><span class="comment">   * the data being transmitted by the logging code.  Packet dumps are obvious examples.</span></div>
<div class="line"><a id="l00304" name="l00304"></a><span class="lineno">  304</span><span class="comment">   *</span></div>
<div class="line"><a id="l00305" name="l00305"></a><span class="lineno">  305</span><span class="comment">   * Note that just because it&#39;s a variable-length structure dump doesn&#39;t mean it&#39;s for Sev::S_DATA severity.</span></div>
<div class="line"><a id="l00306" name="l00306"></a><span class="lineno">  306</span><span class="comment">   * If it&#39;s not frequent, it&#39;s fine for it to even be INFO.  E.g., if I decide to dump every</span></div>
<div class="line"><a id="l00307" name="l00307"></a><span class="lineno">  307</span><span class="comment">   * RST packet, it&#39;s probably okay as Sev::S_INFO, since RSTs are practically rare;</span></div>
<div class="line"><a id="l00308" name="l00308"></a><span class="lineno">  308</span><span class="comment">   * that need not be Sev::S_DATA.  On the other hand, if I dump every DATA packet</span></div>
<div class="line"><a id="l00309" name="l00309"></a><span class="lineno">  309</span><span class="comment">   * as anything except Sev::S_DATA severity, then I should be arrested and convicted.</span></div>
<div class="line"><a id="l00310" name="l00310"></a><span class="lineno">  310</span><span class="comment">   *</span></div>
<div class="line"><a id="l00311" name="l00311"></a><span class="lineno">  311</span><span class="comment">   * When this level is disabled, consider logging a TRACE message instead but summarize the contents you&#39;d</span></div>
<div class="line"><a id="l00312" name="l00312"></a><span class="lineno">  312</span><span class="comment">   * dump; e.g., log a hash and/or a size and/or the few first bytes instead of the entire thing.  Something is</span></div>
<div class="line"><a id="l00313" name="l00313"></a><span class="lineno">  313</span><span class="comment">   * often better than nothing (but nothing is still safer than the whole thing).</span></div>
<div class="line"><a id="l00314" name="l00314"></a><span class="lineno">  314</span><span class="comment">   *</span></div>
<div class="line"><a id="l00315" name="l00315"></a><span class="lineno">  315</span><span class="comment">   * @note This severity *is* part of the *minimalistic* (in-use within Flow) severity set as discussed</span></div>
<div class="line"><a id="l00316" name="l00316"></a><span class="lineno">  316</span><span class="comment">   *       in log::Sev doc header, &quot;Informal semantics&quot; section.</span></div>
<div class="line"><a id="l00317" name="l00317"></a><span class="lineno">  317</span><span class="comment">   */</span></div>
<div class="line"><a id="l00318" name="l00318"></a><span class="lineno">  318</span>  <a class="code hl_enumvalue" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a138fe9b2eb78ab00c84b21c4a6b48fed">S_DATA</a>,</div>
<div class="line"><a id="l00319" name="l00319"></a><span class="lineno">  319</span><span class="comment"></span> </div>
<div class="line"><a id="l00320" name="l00320"></a><span class="lineno">  320</span><span class="comment">  /// Not an actual value but rather stores the highest numerical payload, useful for validity checks.</span></div>
<div class="line"><a id="l00321" name="l00321"></a><span class="lineno">  321</span><span class="comment"></span>  <a class="code hl_enumvalue" href="namespaceflow.html#a3938730ab4b89daf13d027a5f620e7cea6fba12db09e5bebfaa04f6372c41c2cf">S_END_SENTINEL</a></div>
<div class="line"><a id="l00322" name="l00322"></a><span class="lineno">  322</span>}; <span class="comment">// enum class Sev</span></div>
<div class="line"><a id="l00323" name="l00323"></a><span class="lineno">  323</span> </div>
<div class="line"><a id="l00324" name="l00324"></a><span class="lineno">  324</span><span class="comment">// Free functions.</span></div>
<div class="line"><a id="l00325" name="l00325"></a><span class="lineno">  325</span><span class="comment"></span> </div>
<div class="line"><a id="l00326" name="l00326"></a><span class="lineno">  326</span><span class="comment">/**</span></div>
<div class="line"><a id="l00327" name="l00327"></a><span class="lineno">  327</span><span class="comment"> * Deserializes a log::Sev from a standard input stream.  Reads up to but not including the next</span></div>
<div class="line"><a id="l00328" name="l00328"></a><span class="lineno">  328</span><span class="comment"> * non-alphanumeric-or-underscore character; the resulting string is then mapped to a log::Sev.  If none is</span></div>
<div class="line"><a id="l00329" name="l00329"></a><span class="lineno">  329</span><span class="comment"> * recognized, Sev::S_NONE is the result.  The recognized values are:</span></div>
<div class="line"><a id="l00330" name="l00330"></a><span class="lineno">  330</span><span class="comment"> *   - &quot;0&quot;, &quot;1&quot;, ...: Corresponds to the `int` conversion of that log::Sev (e.g., 0 being NONE).</span></div>
<div class="line"><a id="l00331" name="l00331"></a><span class="lineno">  331</span><span class="comment"> *   - Case-insensitive encoding of the non-S_-prefix part of the actual log::Sev member; e.g.,</span></div>
<div class="line"><a id="l00332" name="l00332"></a><span class="lineno">  332</span><span class="comment"> *     &quot;warning&quot; (or &quot;Warning&quot; or &quot;WARNING&quot; or...) for `S_WARNING`.</span></div>
<div class="line"><a id="l00333" name="l00333"></a><span class="lineno">  333</span><span class="comment"> * This enables a few key things to work, including parsing from config file/command line via and conversion from</span></div>
<div class="line"><a id="l00334" name="l00334"></a><span class="lineno">  334</span><span class="comment"> * `string` via `boost::lexical_cast`.</span></div>
<div class="line"><a id="l00335" name="l00335"></a><span class="lineno">  335</span><span class="comment"> *</span></div>
<div class="line"><a id="l00336" name="l00336"></a><span class="lineno">  336</span><span class="comment"> * @param is</span></div>
<div class="line"><a id="l00337" name="l00337"></a><span class="lineno">  337</span><span class="comment"> *        Stream from which to deserialize.</span></div>
<div class="line"><a id="l00338" name="l00338"></a><span class="lineno">  338</span><span class="comment"> * @param val</span></div>
<div class="line"><a id="l00339" name="l00339"></a><span class="lineno">  339</span><span class="comment"> *        Value to set.</span></div>
<div class="line"><a id="l00340" name="l00340"></a><span class="lineno">  340</span><span class="comment"> * @return `is`.</span></div>
<div class="line"><a id="l00341" name="l00341"></a><span class="lineno">  341</span><span class="comment"> */</span></div>
<div class="line"><a id="l00342" name="l00342"></a><span class="lineno">  342</span>std::istream&amp; <a class="code hl_function" href="namespaceflow_1_1log.html#a350b25cb85d91052c0fb3dd80d513056">operator&gt;&gt;</a>(std::istream&amp; is, <a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a>&amp; val);</div>
<div class="line"><a id="l00343" name="l00343"></a><span class="lineno">  343</span><span class="comment">// @todo - `@relatesalso Sev` makes Doxygen complain; maybe it doesn&#39;t work with `enum class`es like Sev.</span></div>
<div class="line"><a id="l00344" name="l00344"></a><span class="lineno">  344</span><span class="comment"></span> </div>
<div class="line"><a id="l00345" name="l00345"></a><span class="lineno">  345</span><span class="comment">/**</span></div>
<div class="line"><a id="l00346" name="l00346"></a><span class="lineno">  346</span><span class="comment"> * Serializes a log::Sev to a standard output stream.  The output string is compatible with the reverse</span></div>
<div class="line"><a id="l00347" name="l00347"></a><span class="lineno">  347</span><span class="comment"> * `istream&gt;&gt;` operator.</span></div>
<div class="line"><a id="l00348" name="l00348"></a><span class="lineno">  348</span><span class="comment"> *</span></div>
<div class="line"><a id="l00349" name="l00349"></a><span class="lineno">  349</span><span class="comment"> * @param os</span></div>
<div class="line"><a id="l00350" name="l00350"></a><span class="lineno">  350</span><span class="comment"> *        Stream to which to serialize.</span></div>
<div class="line"><a id="l00351" name="l00351"></a><span class="lineno">  351</span><span class="comment"> * @param val</span></div>
<div class="line"><a id="l00352" name="l00352"></a><span class="lineno">  352</span><span class="comment"> *        Value to serialize.</span></div>
<div class="line"><a id="l00353" name="l00353"></a><span class="lineno">  353</span><span class="comment"> * @return `os`.</span></div>
<div class="line"><a id="l00354" name="l00354"></a><span class="lineno">  354</span><span class="comment"> */</span></div>
<div class="line"><a id="l00355" name="l00355"></a><span class="lineno">  355</span>std::ostream&amp; <a class="code hl_function" href="namespaceflow_1_1log.html#a06c8c59ea6c9b36c25b9b8ef319ba501">operator&lt;&lt;</a>(std::ostream&amp; os, <a class="code hl_enumeration" href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">Sev</a> val);</div>
<div class="line"><a id="l00356" name="l00356"></a><span class="lineno">  356</span><span class="comment">// @todo - `@relatesalso Sev` makes Doxygen complain; maybe it doesn&#39;t work with `enum class`es like Sev.</span></div>
<div class="line"><a id="l00357" name="l00357"></a><span class="lineno">  357</span><span class="comment"></span> </div>
<div class="line"><a id="l00358" name="l00358"></a><span class="lineno">  358</span><span class="comment">/**</span></div>
<div class="line"><a id="l00359" name="l00359"></a><span class="lineno">  359</span><span class="comment"> * Log_context ADL-friendly swap: Equivalent to `val1.swap(val2)`.</span></div>
<div class="line"><a id="l00360" name="l00360"></a><span class="lineno">  360</span><span class="comment"> * @param val1</span></div>
<div class="line"><a id="l00361" name="l00361"></a><span class="lineno">  361</span><span class="comment"> *        Object.</span></div>
<div class="line"><a id="l00362" name="l00362"></a><span class="lineno">  362</span><span class="comment"> * @param val2</span></div>
<div class="line"><a id="l00363" name="l00363"></a><span class="lineno">  363</span><span class="comment"> *        Object.</span></div>
<div class="line"><a id="l00364" name="l00364"></a><span class="lineno">  364</span><span class="comment"> */</span></div>
<div class="line"><a id="l00365" name="l00365"></a><span class="lineno">  365</span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceflow_1_1log.html#a1b475cd2cc2e476aa96c002927bf1690">swap</a>(Log_context&amp; val1, Log_context&amp; val2);</div>
<div class="line"><a id="l00366" name="l00366"></a><span class="lineno">  366</span><span class="comment"></span> </div>
<div class="line"><a id="l00367" name="l00367"></a><span class="lineno">  367</span><span class="comment">/**</span></div>
<div class="line"><a id="l00368" name="l00368"></a><span class="lineno">  368</span><span class="comment"> * Sets certain `chrono`-related formatting on the given Logger in the current thread that results in a consistent,</span></div>
<div class="line"><a id="l00369" name="l00369"></a><span class="lineno">  369</span><span class="comment"> * desirable output of `duration`s and certain types of `time_point`s.  The effect is that of</span></div>
<div class="line"><a id="l00370" name="l00370"></a><span class="lineno">  370</span><span class="comment"> * util::beautify_chrono_ostream().</span></div>
<div class="line"><a id="l00371" name="l00371"></a><span class="lineno">  371</span><span class="comment"> *</span></div>
<div class="line"><a id="l00372" name="l00372"></a><span class="lineno">  372</span><span class="comment"> * @see flow::async in which new threads are set to use this formatting automatically.  However you&#39;ll want to</span></div>
<div class="line"><a id="l00373" name="l00373"></a><span class="lineno">  373</span><span class="comment"> *      do this explicitly for the startup thread.</span></div>
<div class="line"><a id="l00374" name="l00374"></a><span class="lineno">  374</span><span class="comment"> *</span></div>
<div class="line"><a id="l00375" name="l00375"></a><span class="lineno">  375</span><span class="comment"> * @param logger_ptr</span></div>
<div class="line"><a id="l00376" name="l00376"></a><span class="lineno">  376</span><span class="comment"> *        The Logger to affect in this thread.  Null is allowed; results in no-op.</span></div>
<div class="line"><a id="l00377" name="l00377"></a><span class="lineno">  377</span><span class="comment"> */</span></div>
<div class="line"><a id="l00378" name="l00378"></a><span class="lineno">  378</span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceflow_1_1log.html#aaaaa1dcbf7c8dc99aceb2b6c217187fc">beautify_chrono_logger_this_thread</a>(Logger* logger_ptr);</div>
<div class="line"><a id="l00379" name="l00379"></a><span class="lineno">  379</span><span class="comment"></span> </div>
<div class="line"><a id="l00380" name="l00380"></a><span class="lineno">  380</span><span class="comment">/**</span></div>
<div class="line"><a id="l00381" name="l00381"></a><span class="lineno">  381</span><span class="comment"> * Estimate of memory footprint of the given value, including memory allocated on its behalf -- but</span></div>
<div class="line"><a id="l00382" name="l00382"></a><span class="lineno">  382</span><span class="comment"> * excluding its shallow `sizeof`! -- in bytes.</span></div>
<div class="line"><a id="l00383" name="l00383"></a><span class="lineno">  383</span><span class="comment"> *</span></div>
<div class="line"><a id="l00384" name="l00384"></a><span class="lineno">  384</span><span class="comment"> * @param val</span></div>
<div class="line"><a id="l00385" name="l00385"></a><span class="lineno">  385</span><span class="comment"> *        Value.</span></div>
<div class="line"><a id="l00386" name="l00386"></a><span class="lineno">  386</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00387" name="l00387"></a><span class="lineno">  387</span><span class="comment"> */</span></div>
<div class="line"><a id="l00388" name="l00388"></a><span class="lineno">  388</span><span class="keywordtype">size_t</span> <a class="code hl_function" href="namespaceflow_1_1log.html#a267187e63c6355704f547d794c776747">deep_size</a>(<span class="keyword">const</span> Msg_metadata&amp; val);</div>
<div class="line"><a id="l00389" name="l00389"></a><span class="lineno">  389</span> </div>
<div class="line"><a id="l00390" name="l00390"></a><span class="lineno">  390</span>} <span class="comment">// namespace flow::log</span></div>
<div class="ttc" id="anamespaceboost_1_1filesystem_html"><div class="ttname"><a href="namespaceboost_1_1filesystem.html">boost::filesystem</a></div><div class="ttdoc">We may add some ADL-based overloads into this namespace outside flow.</div><div class="ttdef"><b>Definition:</b> <a href="cfg__fwd_8hpp_source.html#l00266">cfg_fwd.hpp:267</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html"><div class="ttname"><a href="namespaceflow_1_1log.html">flow::log</a></div><div class="ttdoc">Flow module providing logging functionality.</div><div class="ttdef"><b>Definition:</b> <a href="async__file__logger_8cpp_source.html#l00027">async_file_logger.cpp:28</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a06c8c59ea6c9b36c25b9b8ef319ba501"><div class="ttname"><a href="namespaceflow_1_1log.html#a06c8c59ea6c9b36c25b9b8ef319ba501">flow::log::operator&lt;&lt;</a></div><div class="ttdeci">std::ostream &amp; operator&lt;&lt;(std::ostream &amp;os, Sev val)</div><div class="ttdoc">Serializes a log::Sev to a standard output stream.</div><div class="ttdef"><b>Definition:</b> <a href="log_8cpp_source.html#l00242">log.cpp:242</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a1b475cd2cc2e476aa96c002927bf1690"><div class="ttname"><a href="namespaceflow_1_1log.html#a1b475cd2cc2e476aa96c002927bf1690">flow::log::swap</a></div><div class="ttdeci">void swap(Log_context &amp;val1, Log_context &amp;val2)</div><div class="ttdoc">Log_context ADL-friendly swap: Equivalent to val1.swap(val2).</div><div class="ttdef"><b>Definition:</b> <a href="log_8cpp_source.html#l00235">log.cpp:235</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a267187e63c6355704f547d794c776747"><div class="ttname"><a href="namespaceflow_1_1log.html#a267187e63c6355704f547d794c776747">flow::log::deep_size</a></div><div class="ttdeci">size_t deep_size(const Msg_metadata &amp;val)</div><div class="ttdoc">Estimate of memory footprint of the given value, including memory allocated on its behalf – but exclu...</div><div class="ttdef"><b>Definition:</b> <a href="log_8cpp_source.html#l00281">log.cpp:281</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a350b25cb85d91052c0fb3dd80d513056"><div class="ttname"><a href="namespaceflow_1_1log.html#a350b25cb85d91052c0fb3dd80d513056">flow::log::operator&gt;&gt;</a></div><div class="ttdeci">std::istream &amp; operator&gt;&gt;(std::istream &amp;is, Sev &amp;val)</div><div class="ttdoc">Deserializes a log::Sev from a standard input stream.</div><div class="ttdef"><b>Definition:</b> <a href="log_8cpp_source.html#l00262">log.cpp:262</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04">flow::log::Sev</a></div><div class="ttdeci">Sev</div><div class="ttdoc">Enumeration containing one of several message severity levels, ordered from highest to lowest.</div><div class="ttdef"><b>Definition:</b> <a href="log__fwd_8hpp_source.html#l00223">log_fwd.hpp:224</a></div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04a138fe9b2eb78ab00c84b21c4a6b48fed"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a138fe9b2eb78ab00c84b21c4a6b48fed">flow::log::Sev::S_DATA</a></div><div class="ttdeci">@ S_DATA</div><div class="ttdoc">Message satisfies Sev::S_TRACE description AND contains variable-length structure (like packet,...</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04a3ee808b04c34bf6c110e3754de277f7b"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a3ee808b04c34bf6c110e3754de277f7b">flow::log::Sev::S_TRACE</a></div><div class="ttdeci">@ S_TRACE</div><div class="ttdoc">Message indicates any condition that may occur with great frequency (thus verbose if logged).</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04a4aee6034ce9dbc2b5c36f27c80abe021"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a4aee6034ce9dbc2b5c36f27c80abe021">flow::log::Sev::S_WARNING</a></div><div class="ttdeci">@ S_WARNING</div><div class="ttdoc">Message indicates a &quot;bad&quot; condition that is not frequent enough to be of severity Sev::S_TRACE.</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04a9ed9d44ce5760f61ea506d5571343624"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04a9ed9d44ce5760f61ea506d5571343624">flow::log::Sev::S_NONE</a></div><div class="ttdeci">@ S_NONE</div><div class="ttdoc">Sentinel log level that must not be specified for any actual message (at risk of undefined behavior s...</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04aa6874010df179b46ffec47aaf9bc1358"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04aa6874010df179b46ffec47aaf9bc1358">flow::log::Sev::S_DEBUG</a></div><div class="ttdeci">@ S_DEBUG</div><div class="ttdoc">Message indicates a condition with, perhaps, no significant perf impact if enabled (like Sev::S_INFO)...</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04aac04e40d3b2f54f1f517d49594eb7849"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04aac04e40d3b2f54f1f517d49594eb7849">flow::log::Sev::S_ERROR</a></div><div class="ttdeci">@ S_ERROR</div><div class="ttdoc">Message indicates a &quot;bad&quot; condition with &quot;worse&quot; impact than that of Sev::S_WARNING.</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04ac238793326fae17afcc849e96b96e8e7"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04ac238793326fae17afcc849e96b96e8e7">flow::log::Sev::S_INFO</a></div><div class="ttdeci">@ S_INFO</div><div class="ttdoc">Message indicates a not-&quot;bad&quot; condition that is not frequent enough to be of severity Sev::S_TRACE.</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_a5c602384e6fe9d7642740ac2fae4ad04ac90b5a22c7659cc99e7a6d919a14b660"><div class="ttname"><a href="namespaceflow_1_1log.html#a5c602384e6fe9d7642740ac2fae4ad04ac90b5a22c7659cc99e7a6d919a14b660">flow::log::Sev::S_FATAL</a></div><div class="ttdeci">@ S_FATAL</div><div class="ttdoc">Message indicates a &quot;fatally bad&quot; condition, such that the program shall imminently abort,...</div></div>
<div class="ttc" id="anamespaceflow_1_1log_html_aaaaa1dcbf7c8dc99aceb2b6c217187fc"><div class="ttname"><a href="namespaceflow_1_1log.html#aaaaa1dcbf7c8dc99aceb2b6c217187fc">flow::log::beautify_chrono_logger_this_thread</a></div><div class="ttdeci">void beautify_chrono_logger_this_thread(Logger *logger_ptr)</div><div class="ttdoc">Sets certain chrono-related formatting on the given Logger in the current thread that results in a co...</div><div class="ttdef"><b>Definition:</b> <a href="log_8cpp_source.html#l00271">log.cpp:271</a></div></div>
<div class="ttc" id="anamespaceflow_html_a3938730ab4b89daf13d027a5f620e7cea6fba12db09e5bebfaa04f6372c41c2cf"><div class="ttname"><a href="namespaceflow.html#a3938730ab4b89daf13d027a5f620e7cea6fba12db09e5bebfaa04f6372c41c2cf">flow::Flow_log_component::S_END_SENTINEL</a></div><div class="ttdeci">@ S_END_SENTINEL</div><div class="ttdoc">CAUTION – see flow::Flow_log_component doc header for directions to find actual members of this enum ...</div></div>
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